This invention is directed to certain improvements in a float valve of the general character disclosed in my co-pending application entitled FLOAT VALVE, Ser. No. 403,814, filed Oct. 5, 1973, now U.S. Pat. No. 3,893,475, which patent is hereby incorporated into the present disclosure by reference.
In my prior disclosure, the valve casing has an upper supply port controlled by a main valve member and the casing has a rigid bottom wall with a hood extending downward therefrom to form a float chamber confining a float. A diaphragm carrying a main valve member cooperates with the bottom wall of the casing to form a control chamber. Rise in pressure in the control chamber closes the main valve member against the supply port and a drop in pressure retracts the main valve member to open position. Water pressure is supplied to the control chamber through a small conduit means in the form of an upright tube that is carried by the valve member and extends upward through and beyond the supply port.
To open the supply port, pressure is reduced in the control chamber by a bleeder port in the rigid bottom wall of the valve casing and the bleeder port is controlled by a small upright pilot valve member which is fixedly mounted on the upper side of the float. The pilot valve member is a simple pin which cooperates with a valve seat in the form of a small O-ring that is held in assembled position by a suitable annular retainer member.
The small tube projecting upward from the main valve member is slidingly embraced by a spider in the supply port and a screen carried by the spider keeps large sand particles out of the control chamber. The hood that extends downward from the control chamber has a vent which is sufficiently restricted to trap a body of air in the path of ascent of the float on each float cycle and thus cause the rise in liquid level inside the hood to lag behind the rise in liquid level outside the hood. The liquid level outside the hood must rise enough above the liquid level inside the hood to compress the trapped air sufficiently to permit the float to rise high enough to close the pilot valve. Thus, the trapped air has the effect of raising the normal level in the tank that is supplied by the float valve. The resulting increase in the volume of water that is released on each float cycle desirably decreases the frequency of the float cycle that is required to supply a given total volume of water over a given period of time.